U.S. patent application number 17/024656 was filed with the patent office on 2021-03-18 for method for building predictive model of microorganism-derived dissolved organic nitrogen in wastewater.
The applicant listed for this patent is Nanjing University. Invention is credited to Haidong HU, Kewei LIAO, Hongqiang REN.
Application Number | 20210081587 17/024656 |
Document ID | / |
Family ID | 1000005136459 |
Filed Date | 2021-03-18 |
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United States Patent
Application |
20210081587 |
Kind Code |
A1 |
HU; Haidong ; et
al. |
March 18, 2021 |
METHOD FOR BUILDING PREDICTIVE MODEL OF MICROORGANISM-DERIVED
DISSOLVED ORGANIC NITROGEN IN WASTEWATER
Abstract
A method for building a predictive model of mDON in wastewater,
including a) acquiring a kinetics associated with production and
consumption of a mDON of an activated sludge system, and importing
a kinetic expression of the mDON into a conventional activated
sludge model No. 1 (ASM1) to build a kinetic equation for the mDON;
b) inputting component variables, parameter variables, model
matrices, process rate equation and operating parameters of a
predictive model into a simulation software AquaSim to build an
ASM-mDON model; c) inputting initial values of the component
variables and the parameter variables into the simulation software
AquaSim for model initialization; d) acquiring initial mDON kinetic
and sensitivity analysis results, selecting corresponding
parameters, calibrating kinetic and stoichiometric parameters of
the ASM-mDON model using a parameter estimation function of the
simulation software AquaSim; and e) replacing the initial values of
the ASM-mDON model with optimal values obtained in d).
Inventors: |
HU; Haidong; (Nanjing,
CN) ; LIAO; Kewei; (Nanjing, CN) ; REN;
Hongqiang; (Nanjing, CN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Nanjing University |
Nanjing |
|
CN |
|
|
Family ID: |
1000005136459 |
Appl. No.: |
17/024656 |
Filed: |
September 17, 2020 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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PCT/CN2019/119772 |
Nov 20, 2019 |
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17024656 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C02F 2101/38 20130101;
C02F 2209/15 20130101; C02F 2209/16 20130101; C02F 2209/08
20130101; C02F 3/006 20130101; G06F 30/27 20200101; C02F 1/44
20130101; C02F 2209/22 20130101; C02F 2209/14 20130101; G06F
2111/10 20200101 |
International
Class: |
G06F 30/27 20060101
G06F030/27; C02F 3/00 20060101 C02F003/00 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 12, 2019 |
CN |
201910861998.7 |
Claims
1. A method, comprising: a) acquiring a kinetics associated with
production and consumption of a mDON of an activated sludge system,
and importing a kinetic expression of the mDON into a conventional
activated sludge model No. 1 (ASM1) to build a kinetic equation for
the mDON; b) inputting component variables, parameter variables,
model matrices, process rate equation and operating parameters of a
predictive model into a simulation software AquaSim to build an
ASM-mDON model; c) inputting initial values of the component
variables and the parameter variables into the simulation software
AquaSim for model initialization; d) acquiring initial mDON kinetic
and sensitivity analysis results, selecting corresponding
parameters, calibrating kinetic and stoichiometric parameters of
the ASM-mDON model using a parameter estimation function of the
simulation software AquaSim, thereby predicting a concentration of
the mDON; and e) replacing the initial values of the ASM-mDON model
with optimal values obtained by the parameter estimation function
in d), thereby optimizing the model.
2. The method of claim 1, wherein the activated sludge system
comprises a fully mixed steady state activated sludge: the
activated sludge has a sludge age of 5-30 days, and a concentration
of 2000-5000 mg/L.
3. The method of claim 1, wherein the ASM-mDON model is used for
study of the mDON released by microorganisms in the activated
sludge system, and the model comprises: seven components:
heterotrophic bacteria X.sub.H, autotrophic bacteria X.sub.A, inert
particles X.sub.I, nitrate nitrogen S.sub.NO, ammonia nitrogen
S.sub.NH, microorganism-derived dissolved organic nitrogen
S.sub.DON, dissolved oxygen S.sub.O; five reaction processes: a
growth process and an endogenous respiration process of
heterotrophic bacteria using ammonium chloride as a substrate; a
growth process and an endogenous respiration process of autotrophic
bacteria using ammonium chloride as a substrate; and an
ammonization process of mDON; and eighteen parameters: maximum
specific growth rate {circumflex over (.mu.)}.sub.H of
heterotrophic bacteria, yield coefficient Y.sub.H of heterotrophic
bacteria, attenuation coefficient b.sub.H of heterotrophic
bacteria, half-saturation constant K.sub.H,NH for ammonia nitrogen
of heterotrophic bacteria, half-saturation constant K.sub.H,O for
dissolved oxygen of heterotrophic bacteria, maximum specific growth
rate {circumflex over (.mu.)}.sub.A of autotrophic bacteria,
substrate utilization ratio f.sub.H,DON of heterotrophic bacteria
converting the substrate into the mDON, yield coefficient Y.sub.A
of autotrophic bacteria, attenuation coefficient b.sub.A of
autotrophic bacteria, half-saturation constant K.sub.A,NH for
ammonia nitrogen of autotrophic bacteria, half-saturation constant
K.sub.A,O for dissolved oxygen of autotrophic bacteria, substrate
utilization ratio f.sub.A,DON of autotrophic bacteria converting
the substrate into the mDON, proportion of nitrogen i.sub.XB in an
organism, proportion of nitrogen i.sub.XP in the product of the
organism, substrate utilization ratio f.sub.NO of autotrophic
bacteria converting the substrate into the nitrate nitrogen,
proportion of inert particles f.sub.I yielded in the organism,
ammonification rate k.sub.a, and half-saturation constant
K.sub.H,DON for mDON.
4. The method of claim 3, wherein change rates of the seven
components of the ASM-mDON model satisfy with the following
formulas: X H : dX H dt = .mu. ^ H M H , NH ( t ) M H , O ( t ) X H
( t ) - b H M H , O ( t ) X H ( t ) ( 1 ) X A : dX A dt = .mu. ^ A
M A , NH ( t ) M A , O ( t ) X A ( t ) - b A M A , O ( t ) X A ( t
) ( 2 ) S NH : dS NH dt = - ( f H , DON Y H + i XB ) .mu. ^ H M H ,
NH ( t ) M H , O ( t ) X H ( t ) - ( f A , DON + f NO Y A + i XB )
.mu. ^ A M A , NH ( t ) M A , O ( t ) X A ( t ) + k a M H , DON ( t
) X H ( t ) ( 3 ) S DON : dS DON dt = f H , DON Y H .mu. ^ H M H ,
NH ( t ) M H , O ( t ) X H ( t ) + f A , DON Y A .mu. ^ A M A , NH
( t ) M A , O ( t ) X A ( t ) - k a M H , DON ( t ) X H ( t ) ( 4 )
S NO : dS NO dt = f NO Y A .mu. ^ A M A , NH ( t ) M A , O ( t ) X
A ( t ) ( 5 ) X I : dX I dt = f I b H M H , O ( t ) X H ( t ) + f I
b A M A , O ( t ) X A ( t ) ( 6 ) S O : dS O dt = k L .alpha. ( S O
* - S O ) - ( 1 - 2.86 f H , DON Y H ) .mu. ^ H M H , NH ( t ) M H
, O ( t ) X H ( t ) - ( 1 - 2.86 f A , DON Y A - 4.57 f NO Y A )
.mu. ^ A M A , NH ( t ) M A , O ( t ) X A ( t ) + ( i XB - f I i XP
) b H M H , O ( t ) X H ( t ) + ( i XB - f I i XP ) b A M A , O ( t
) X A ( t ) ( 7 ) ##EQU00017## M.sub.H,NH(t) is a Monod term
determined by the substrate for the heterotrophic bacteria:
M.sub.A,NH(t) is a Monod term determined by the substrate for the
autotrophic bacteria; M.sub.H,O(t) is a Monod term determined by
the dissolved oxygen for the heterotrophic bacteria; M.sub.A,O(t)
is a Monod term determined by the dissolved oxygen for the
autotrophic bacteria; M.sub.H,DON(t) is a Monod term determined by
the mDON in the heterotrophic bacteria: k.sub.L.alpha. is an
exchange rate between a gas phase and a liquid phase; and S.sub.O*
is a maximum solubility of oxygen.
5. The method of claim 3, wherein the mDON in wastewater is
calculated using the following kinetic equation: dS DON dt = f H ,
DON Y H .mu. ^ H M H , NH ( t ) M H , O ( t ) X H ( t ) + f A , DON
Y A .mu. ^ A M A , NH ( t ) M A , O ( t ) X A ( t ) - k a M H , DON
( t ) X H ( t ) . ( 8 ) ##EQU00018##
6. The method of claim 3, wherein a single-step size of the
AMS-mDON model is 0.1, and a total response time for the predictive
model is a product of a calculation capacity and the single-step
size.
7. A method for predicting a concentration of mDON in wastewater,
the method comprising: 1) building the ASM-mDON model according to
the method of claim 1; 2) determining components of an influent and
the parameters of the ASM-mDON model, comprising: filtering an
influent sample from a wastewater treatment plant using a membrane
filter; measuring chemical oxygen demand (COD), concentrations of
total nitrogen, nitrate nitrogen, nitrite nitrogen, ammonia
nitrogen, and dissolved organic nitrogen of the influent sample
filtered, respectively; and measuring yield coefficient Y.sub.H of
heterotrophic bacteria, attenuation coefficient b.sub.H
heterotrophic bacteria, and maximum specific growth rate
{circumflex over (.mu.)}.sub.H of heterotrophic bacteria for the
activated sludge; and 3) predicting the concentration of the mDON
in wastewater, comprising: inputting the components and parameters
obtained in 2) into the ASM-mDON model to estimate the
concentration of the mDON in the wastewater.
8. The method of claim 7, wherein in 2), the wastewater treatment
plant operates at an ambient temperature ranging from 15 to
25.degree. C., and an influent pH thereof is 6.0-8.0.
9. The method of claim 7, wherein in 2), the concentration of the
dissolved organic nitrogen is a difference between concentrations
of total nitrogen and ammonia nitrogen, nitrate nitrogen and
nitrite nitrogen; the concentration of the total nitrogen is
measured by using potassium persulfate oxidation-ion
chromatography, or potassium persulfate oxidation-ultraviolet
spectrophotometry; the concentration of the ammonia nitrogen is
measured by using salicylic acid-hypochlorite spectrophotometry;
the concentration of the nitrate nitrogen is measured by using the
ion chromatography or ultraviolet-visible spectrophotometry; the
concentration of the nitrite nitrogen is measured by using ion
chromatography or N-(1-naphthyl)-ethylenediamine spectrophotometry;
and the COD is measured by using potassium dichromate method or
rapid digestion method.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation-in-part of International
Patent Application No. PCT/CN2019/119772 with an international
filing date of Nov. 20, 2019, designating the United States, now
pending, and further claims foreign priority benefits to Chinese
Patent Application No. 201910861998.7 filed Sep. 12, 2019. The
contents of all of the aforementioned applications, including any
intervening amendments thereto, are incorporated herein by
reference. Inquiries from the public to applicants or assignees
concerning this document or the related applications should be
directed to: Matthias Scholl P. C., Attn.: Dr. Matthias Scholl
Esq., 245 First Street, 18th Floor, Cambridge, Mass. 02142.
BACKGROUND
[0002] The disclosure relates to the field of wastewater treatment,
and more particularly, to a method for building a predictive model
of microorganism-derived dissolved organic nitrogen (mDON) in
wastewater and to application thereof.
[0003] The effluent of the municipal wastewater treatment plants
includes dissolved organic nitrogen (DON). In general, the DON
includes influent-derived dissolved organic nitrogen (inDON) which
is non-degradable and microorganism-derived dissolved organic
nitrogen produced in the biological sewage treatment process.
Compared with inDON, mDON produced in the wastewater treatment
process is more easily affected by the process parameters and
conditions, and the composition and properties of mDON are closely
related to the growth and metabolism of microorganisms in the
biological treatment process.
[0004] Although the mDON in the sewage treatment plant has
attracted increasing attention, there is no direct method to
determine mDON in the sewage treatment plant.
SUMMARY
[0005] The disclosure provides a method for building a predictive
model of microorganism-derived dissolved organic nitrogen (mDON) in
wastewater. Specifically, based on the operating parameters of an
activated sludge process, the component concentrations, and the
kinetic and stoichiometric parameters of the influent of a sewage
plant, an activated sludge model (ASM)-mDON predictive model is
built.
[0006] Provided is a method for building a predictive model of mDON
in wastewater, the method comprising: [0007] a) acquiring a
kinetics associated with production and consumption of a mDON of an
activated sludge system, and importing a kinetic expression of the
mDON into a conventional activated sludge model No. 1 (ASM1) to
build a kinetic equation for the mDON; [0008] b) inputting
component variables, parameter variables, model matrices, process
rate equation and operating parameters of a predictive model into a
simulation software AquaSim to build an ASM-mDON model; [0009] c)
inputting initial values of the component variables and the
parameter variables into the simulation software AquaSim for model
initialization; [0010] d) acquiring initial mDON kinetic and
sensitivity analysis results, selecting corresponding parameters,
calibrating kinetic and stoichiometric parameters of the ASM-mDON
model using a parameter estimation function of the simulation
software AquaSim, thereby predicting a concentration of the mDON;
and [0011] e) replacing the initial values of the ASM-mDON model
with optimal values obtained by the parameter estimation function
in d), thereby optimizing the model.
[0012] The activated sludge system comprises a fully mixed steady
state activated sludge; the activated sludge has a sludge age of
5-30 days, and a concentration of 2000-5000 mg/L.
[0013] In c), the initial values of the parameter variables are
determined with reference to "Mathematical Model for Activated
Sludge". The kinetic and stoichiometric parameters of the ASM-mDON
model are classified for parameter assumption, parameter
estimation, or default argument assignment.
[0014] In d), the sensitivity analysis uses the absolute-relative
sensitivity equation to determine the influence of different values
of an independent parameter on the estimation of the mDON.
[0015] The ASM-mDON model is used for study of the mDON released by
microorganisms in the activated sludge system, and the model
comprises: [0016] seven components: heterotrophic bacteria X.sub.H,
autotrophic bacteria X.sub.A, inert particles X.sub.1, nitrate
nitrogen S.sub.NO, ammonia nitrogen S.sub.NH, microorganism-derived
dissolved organic nitrogen S.sub.DON, dissolved oxygen S.sub.O;
[0017] five reaction processes: the growth process and endogenous
respiration process of heterotrophic bacteria using ammonium
chloride as a substrate; the growth process and endogenous
respiration process of autotrophic bacteria using ammonium chloride
as a substrate; and the ammonization process of mDON; [0018]
eighteen parameters: maximum specific growth rate {circumflex over
(.mu.)}.sub.H of heterotrophic bacteria, yield coefficient Y.sub.H
of heterotrophic bacteria, attenuation coefficient b.sub.H of
heterotrophic bacteria, half-saturation constant K.sub.H,NH for
ammonia nitrogen of heterotrophic bacteria, half-saturation
constant K.sub.H,O for dissolved oxygen of heterotrophic bacteria,
maximum specific growth rate {circumflex over (.mu.)}.sub.A of
autotrophic bacteria, substrate utilization ratio f.sub.H,DON of
heterotrophic bacteria converting the substrates into the mDON,
yield coefficient Y.sub.A of autotrophic bacteria, attenuation
coefficient b.sub.A of autotrophic bacteria, half-saturation
constant K.sub.A,NH for ammonia nitrogen of autotrophic bacteria,
half-saturation constant K.sub.A,O for dissolved oxygen of
autotrophic bacteria, substrate utilization ratio f.sub.A,DON of
autotrophic bacteria converting the substrates into the mDON,
proportion of nitrogen i.sub.XB in the organism, proportion of
nitrogen i.sub.XP in the product of the organism, substrate
utilization ratio f.sub.NO of autotrophic bacteria converting the
substrates into the nitrate nitrogen, proportion of inert particles
f.sub.I yielded in the organism, ammonification rate k.sub.a, and
half-saturation constant K.sub.H,DON for mDON.
[0019] The change rates of the seven components of the ASM-mDON
model satisfy with the following formulas:
X H : dX H dt = .mu. ^ H M H , NH ( t ) M H , O ( t ) X H ( t ) - b
H M H , O ( t ) X H ( t ) ( 1 ) X A : dX A dt = .mu. ^ A M A , NH (
t ) M A , O ( t ) X A ( t ) - b A M A , O ( t ) X A ( t ) ( 2 ) S
NH : dS NH dt = - ( f H , DON Y H + i XB ) .mu. ^ H M H , NH ( t )
M H , O ( t ) X H ( t ) - ( f A , DON + f NO Y A + i XB ) .mu. ^ A
M A , NH ( t ) M A , O ( t ) X A ( t ) + k a M H , DON ( t ) X H (
t ) ( 3 ) S DON : dS DON dt = f H , DON Y H .mu. ^ H M H , NH ( t )
M H , O ( t ) X H ( t ) + f A , DON Y A .mu. ^ A M A , NH ( t ) M A
, O ( t ) X A ( t ) - k a M H , DON ( t ) X H ( t ) ( 4 ) S NO : dS
NO dt = f NO Y A .mu. ^ A M A , NH ( t ) M A , O ( t ) X A ( t ) (
5 ) X I : dX I dt = f I b H M H , O ( t ) X H ( t ) + f I b A M A ,
O ( t ) X A ( t ) ( 6 ) S O : dS O dt = k L .alpha. ( S O * - S O )
- ( 1 - 2.86 f H , DON Y H ) .mu. ^ H M H , NH ( t ) M H , O ( t )
X H ( t ) - ( 1 - 2.86 f A , DON Y A - 4.57 f NO Y A ) .mu. ^ A M A
, NH ( t ) M A , O ( t ) X A ( t ) + ( i XB - f I i XP ) b H M H ,
O ( t ) X H ( t ) + ( i XB - f I i XP ) b A M A , O ( t ) X A ( t )
( 7 ) ##EQU00001##
where M.sub.H,NH(t) is a Monod term determined by the substrate for
the heterotrophic bacteria; M.sub.A,NH(t) is a Monod term
determined by the substrate for the autotrophic bacteria;
M.sub.H,O(t) is a Monod term determined by the dissolved oxygen for
the heterotrophic bacteria; M.sub.A,O(t) is a Monod term determined
by the dissolved oxygen for the autotrophic bacteria;
M.sub.H,DON(t) is a Monod term determined by the mDON in the
heterotrophic bacteria; k.sub.L.alpha. is an exchange rate between
the gas phase and the liquid phase; S.sub.O* is the maximum
solubility of oxygen.
[0020] The mDON in the wastewater is calculated using the following
kinetic equation:
dS DON dt = f H , DON Y H .mu. ^ H M H , NH ( t ) M H , O ( t ) X H
( t ) + f A , DON Y A .mu. ^ A M A , NH ( t ) M A , O ( t ) X A ( t
) - k a M H , DON ( t ) X H ( t ) ( 8 ) ##EQU00002##
[0021] The single-step size of the AMS-mDON model is 0.1, and the
total response time for the predictive model is the product of the
calculation capacity and the single-step size.
[0022] The disclosure also provides a method for predicting a
concentration of mDON in wastewater, the method comprising: [0023]
1) building the ASM-mDON model; [0024] 2) determining the
components of an influent and the parameters of the ASM-mDON model:
filtering influent samples from a wastewater treatment plant using
a membrane filter; measuring the chemical oxygen demand (COD),
concentrations of total nitrogen, nitrate nitrogen, nitrite
nitrogen, ammonia nitrogen, and dissolved organic nitrogen of the
filtered influent samples, respectively; and measuring yield
coefficient Y.sub.H of heterotrophic bacteria, attenuation
coefficient b.sub.H heterotrophic bacteria, and maximum specific
growth rate {circumflex over (.mu.)}.sub.H of heterotrophic
bacteria for the activated sludge; and [0025] 3) predicting the
concentration of the mDON in wastewater: inputting the components
and parameters obtained in 2) into the ASM-mDON model to estimate
the concentration of the mDON in the wastewater.
[0026] In 2), the wastewater treatment plant operates at the
ambient temperature ranging from 15 to 25.degree. C., and an
influent pH thereof is 6.0-8.0.
[0027] In 2), the membrane filter is a cellulose acetate membrane
filter having pore size of 0.45 .mu.m.
[0028] In 2), the initial values of parameter variables are
determined with reference to "Mathematical Model of Activated
Sludge". The kinetic and stoichiometric parameters of the ASM-mDON
model are classified for parameter assumption, parameter
estimation, or default argument assignment.
[0029] In 2), the concentration of the dissolved organic nitrogen
is the difference between the total nitrogen and ammonia nitrogen,
nitrate nitrogen and nitrite nitrogen; the concentration of total
nitrogen is measured by using potassium persulfate oxidation-ion
chromatography, or potassium persulfate oxidation-ultraviolet
spectrophotometry; the concentration of ammonia nitrogen is
measured by using salicylic acid-hypochlorite spectrophotometry;
the nitrate nitrogen is measured by using the ion chromatography or
ultraviolet-visible spectrophotometry; the nitrite nitrogen is
measured by using ion chromatography or
N-(1-naphthyl)-ethylenediamine spectrophotometry; and the COD is
measured by using potassium dichromate method or rapid digestion
method.
[0030] The following advantages are associated with the method for
building a predictive model of mDON in wastewater in accordance
with the disclosure:
[0031] (1) The ASM-mDON model can predict the concentration of the
mDON in the wastewater, distinguish the mDON from the inDON, and
quantify the concentration of the mDON released from the activated
sludge in the wastewater treatment plant.
[0032] (2) The method uses a simplified ASM model, and necessary
kinetic and stoichiometric parameters to build an ASM-mDON model
for predicting the concentration of the mDON in the wastewater,
which simplifies the operations and improves the prediction
accuracy.
[0033] (3) The method can be widely applied in simulating and
predicting the concentration of the mDON, laying the foundation for
optimization of water quality in the wastewater treatment
plants.
BRIEF DESCRIPTION OF THE DRAWINGS
[0034] FIG. 1 is a flow chart of a method for building a predictive
model of mDON according to one embodiment of the disclosure;
[0035] FIG. 2 is a graft showing the predictive result of the
concentration of the mDON according to one embodiment of the
disclosure; and
[0036] FIG. 3 is a graft showing the predictive result of the
concentration of the mDON according to verification embodiment of
the disclosure.
DETAILED DESCRIPTION
[0037] To further illustrate the disclosure, embodiments detailing
a method for building a predictive model of mDON in wastewater are
described below. It should be noted that the following embodiments
are intended to describe and not to limit the disclosure.
Example 1
[0038] The example was a simulation of the operation of a
laboratory-scale sequencing batch reactor (SBR) for the treatment
of activated sludge. As a raw material, the wastewater containing
particular compositions (excluding dissolved organic nitrogen) was
prepared to support the growth of microorganisms in the activated
sludge. The prepared wastewater contained the following
compositions: 300.+-.30 mg/L COD, 20.+-.5 mg/L total nitrogen, and
3.5.+-.0.5 mg/L total phosphorus. The operating parameters of the
sequencing batch reactor: the effective volume of 2 L, the
operating cycle of 6 h, and the hydraulic retention time of 12 h,
and the activated sludge age of 20 d. The operating mode of the
sequencing batch reactor at ambient temperature of 25.degree. C.:
the inlet valve opens and the influent was filled in, followed by
mixing and aeration for 300 min. The mixed liquor was sedimented
for 50 min and the supernatant was drained out of the sequencing
batch reactor. The activated sludge in the sequencing batch reactor
had a concentration within the range of 2000-200 mg/L, and a pH
value of 7.5.+-.0.5. Referring to FIG. 1, a method for building a
predictive model of mDON in wastewater comprises:
[0039] 1. Building the ASM-mDON Model:
[0040] The inputs to the ASM-mDON model comprises: X.sub.H
(concentration of heterotrophic bacteria), X.sub.A (concentration
of autotrophic bacteria), X.sub.I (concentration of inert
particles), S.sub.NO (concentration of nitrate nitrogen), S.sub.NH
(concentration of ammonia nitrogen), S.sub.DON (concentration of
the mDON), S.sub.O (concentration of dissolved oxygen), which were
state variables; the model matrix corresponding to the process rate
equation for the components were inputted into the reaction process
included in the software, thereby building a simulation of the
sequencing batch reactor for the treatment of activated sludge.
[0041] The simulation model was the simplified ASM-mDON model as
shown in Table 1:
TABLE-US-00001 TABLE 1 Process rate equations for components
Components Process rate equation No. X.sub.H d X H d t = .mu. ^ H M
H , NH ( t ) M H , O ( t ) X H ( t ) - b H M H , O ( t ) X H ( t )
##EQU00003## (1) X.sub.A d X A d t = .mu. ^ A M A , NH ( t ) M A ,
O ( t ) X A ( t ) - b A M A , O ( t ) X A ( t ) ##EQU00004## (2)
S.sub.NH dS NH dt = - ( f H , DON Y H + i XB ) .mu. ^ H M H , NH (
t ) M H , O ( t ) X H ( t ) - ( f A , DON + f NO Y A + i XB ) .mu.
^ A M A , NH ( t ) M A , O ( t ) X A ( t ) + k a M H , DON ( t ) X
H ( t ) ##EQU00005## (3) S.sub.DON dS DON dt = f H , DON Y H .mu. ^
H M H , NH ( t ) M H , O ( t ) X H ( t ) + f A , DON Y A .mu. ^ A M
A , NH ( t ) M A , O ( t ) X A ( t ) - k a M H , DON ( t ) X H ( t
) ##EQU00006## (4) S.sub.NO dS NO dt = f NO Y A .mu. ^ A M A , NH (
t ) M A , O ( t ) X A ( t ) ##EQU00007## (5) X.sub.I d X I d t = f
I b H M H , O ( t ) X H ( t ) + f I b A M A , O ( t ) X A ( t )
##EQU00008## (6) S.sub.O dS O d t = k L .alpha. ( S O * - S O ) - (
1 - 2.86 f H , DON Y H ) .mu. ^ H M H , NH ( t ) M H , O ( t ) X H
( t ) - ( 1 - 2.86 f A , DON Y A - 4.57 f NO Y A ) .mu. ^ A M A ,
NH ( t ) M A , O ( t ) X A ( t ) + ( i XB - f I i XP ) b H M H , O
( t ) X H ( t ) + ( i XB - f I i XP ) b A M A , O ( t ) X A ( t )
##EQU00009## (7) where M.sub.H,NM(t) is the Monod term determined
by the substrate for the heterotrophic bacteria; M.sub.A,NH(t) is
the Monod term determined by the substrate for the autotrophic
bacteria; M.sub.H,O(t) is the Monod term determined by the
dissolved oxygen for the heterotrophic bacteria; M.sub.A,O(t) is
the Monod term determined by the dissolved oxygen for the
autotrophic bacteria; M.sub.H,DON(t) is the Monod term determined
by the mDON in the heterotrophic bacteria; k.sub.L.alpha. is the
exchange rate between the gas phase and the liquid phase;
S.sub.O.sup.* is the maximum solubility of oxygen.
[0042] The model matrix corresponding to the process rate equation
for the components were shown in Table 2:
TABLE-US-00002 TABLE 2 Matrix imported into reaction process
included in software Reaction process X.sub.H X.sub.A S.sub.NH
S.sub.DON S.sub.NO X.sub.I S.sub.O Process rate equation Growth of
heterotrophic 1 - f H , DON Y H - i XB ##EQU00010## f H , DON Y H
##EQU00011## 1 - 2.86 f H , DON Y H ##EQU00012## {circumflex over
(.mu.)}.sub.HM.sub.H,NH(t)M.sub.H,O(t)X.sub.H(t) bacteria Growth of
autotrophic 1 - f A , DON + f I Y A - i XB ##EQU00013## f A , DON Y
A ##EQU00014## f NO Y A ##EQU00015## 1 - 2.86 f A , DON Y A - 4.57
f NO Y A ##EQU00016## {circumflex over
(.mu.)}.sub.AM.sub.A,NH(t)M.sub.A,O(t)X.sub.A(t) bacteria
Endogenous -1 f.sub.I b.sub.HM.sub.H,O(t)X.sub.H(t) respiration of
heterotrophic bacteria Endogenous -1 f.sub.I
b.sub.AM.sub.A,O(t)X.sub.A(t) respiration of autotrophic bacteria
Arnmonization 1 -1 k.sub.aM.sub.H,DON(t)X.sub.H(t)
[0043] 2. Determining the components of influent and the values of
model parameters of the ASM-mDON model:
[0044] 50 mL of influent was sampled directly from the sequencing
batch reactor, and filtered using a cellulose acetate membrane
filter having pore size of 0.45 .mu.m. The concentration of total
nitrogen was 20 mg/L measured by using potassium persulfate
oxidation-ion chromatography, or potassium persulfate
oxidation-ultraviolet spectrophotometry; the concentration of
ammonia nitrogen was 20 mg/L measured by using salicylic
acid-hypochlorite spectrophotometry; the nitrate nitrogen was 0
mg/L measured by using the ion chromatography or
ultraviolet-visible spectrophotometry; the nitrite nitrogen was 0
mg/L measured by using ion chromatography or
N-(1-naphthyl)-ethylenediamine spectrophotometry; and the COD was
300 mg/L measured by using potassium dichromate method or rapid
digestion method. The concentration of the dissolved organic
nitrogen was 0 mg/L, that is, the difference between the sum of
total nitrogen and ammonia nitrogen and the sum of nitrate nitrogen
and nitrite nitrogen.
[0045] The default values for kinetics and stoichiometric
parameters of the conventional model, and the water quality
parameters determined in 1) were used for simulation of parameters
in relation to the mDON yielded in the wastewater treatment
process; the simulation parameters were set as follows: {circumflex
over (.mu.)}.sub.H, 0.8 h.sup.-1, Y.sub.H, 0.67 mg (COD)/mg (N);
b.sub.H, 0.62 h.sup.-1; K.sub.H,NH, 0.05 mg (N)/L; K.sub.H,O, 0.2
mg (N)/L; {circumflex over (.mu.)}.sub.A, 0.3 h.sup.-1;
f.sub.H,DON, 0.04; Y.sub.A, 3.4 mg (COD)/mg (N); b.sub.A, 0.15
h.sup.-1; K.sub.A,NH, 5 mg (N)/L; K.sub.A,O, 0.4 mg (N)/L;
f.sub.A,DON, 0.04, i.sub.XB, 0.07 mg (N)/mg (COD); i.sub.XP, 0.03
mg (N)/mg (COD); f.sub.NO, 0.8; f.sub.I, 0.2; k.sub.a, 0.04 L/(mg
(N)d); K.sub.H,DON, 1.5 mg (N)/L; where pH was the maximum specific
growth rate of heterotrophic bacteria, Y.sub.H was the yield
coefficient of heterotrophic bacteria, b.sub.H was the attenuation
coefficient of heterotrophic bacteria, K.sub.H,NH was the
half-saturation constant for ammonia nitrogen of heterotrophic
bacteria, K.sub.H,O was the half-saturation constant for dissolved
oxygen of heterotrophic bacteria, {circumflex over (.mu.)}.sub.A
was the maximum specific growth rate of autotrophic bacteria,
f.sub.H,DON was the substrate utilization ratio of heterotrophic
bacteria converting the substrates into the mDON, Y.sub.A was the
yield coefficient of autotrophic bacteria, b.sub.A was the
attenuation coefficient of autotrophic bacteria, K.sub.A,NH was the
half-saturation constant for ammonia nitrogen of autotrophic
bacteria, K.sub.A,O was the half-saturation constant for dissolved
oxygen of autotrophic bacteria, f.sub.A,DON was the substrate
utilization ratio of autotrophic bacteria converting the substrates
into the mDON, i.sub.XB was the proportion of nitrogen in the
organism, i.sub.XP was the proportion of nitrogen in the product of
the organism. f.sub.NO was the substrate utilization ratio of
autotrophic bacteria converting the substrates into the nitrate
nitrogen, f.sub.I was the rate of inert particles yielded in the
organism, k.sub.a was the ammonification rate. K.sub.H,DON was the
half-saturation constant for mDON.
[0046] 3. Predicting the concentration of mDON in wastewater:
[0047] The components of influent and values of model parameters
determined in 2) were fed into the software for modeling mDON to
predict the concentration of the mDON in wastewater; where the
single-step size was 0.1, and the calculation capacity was 60
steps, and the simulation process was based on the mDON
participating in the biochemical reactions. The model-predicted
result was shown in FIG. 2.
Example 2
[0048] The example was the same as Example 1, except for the
influent from the municipal wastewater treatment plant A. The
operating parameters of the sequencing batch reactor: the influent
temperature was 15.degree. C., and hydraulic retention time was 8
h, activated sludge age was 20 d. The influent contains the
following compositions: COD 96.2-120.6 mg/L, total nitrogen
23.7-29.1 mg/L, total phosphorus 2.0-3.5 mg/L, pH 7.4-8.0, and
inert particles 3000-3200 mg/L. The influent (of greater than 200
mL) in the biological treatment process (i.e. oxidation ditch) and
the activated sludge (of greater than 50 mL) were sampled for
analysis of the components of the influent, as well as parameter
estimation. The influent sample was then filtered using a cellulose
acetate membrane filter having pore size of 0.45 .mu.m. The COD was
measured by using potassium dichromate method or rapid digestion
method; the concentration of total nitrogen was measured by using
potassium persulfate oxidation-ion chromatography, or potassium
persulfate oxidation-ultraviolet spectrophotometry; the
concentration of ammonia nitrogen was measured by using salicylic
acid-hypochlorite spectrophotometry; the nitrate nitrogen was
measured by using the ion chromatography or ultraviolet-visible
spectrophotometry; the nitrite nitrogen was measured by using ion
chromatography or N-(1-naphthyl)-ethylenediamine spectrophotometry;
the concentration of dissolved organic nitrogen was the difference
between the sum of total nitrogen and ammonia nitrogen and the sum
of nitrate nitrogen and nitrite nitrogen. According to the
parameters determined in 1), the initial values of the yield
coefficient (Y.sub.H) of heterotrophic bacteria, the attenuation
coefficient of heterotrophic bacteria, and the maximum specific
growth rate ({circumflex over (.mu.)}.sub.H) of heterotrophic
bacteria were 0.26 mgCOD/mgN, 0.09 h.sup.-1, and 1.0 h.sup.-1,
respectively.
[0049] Building the ASM-mDON model and finding the optimal
parameter values i.sub.XB by parameter estimation: 0.07 mg (N)/mg
(COD); k.sub.a, 0.04 L/(mg (N)d); {circumflex over (.mu.)}.sub.H,
1.0 h.sup.-1; Y.sub.H, 0.30 mg (COD)/mg (N); b.sub.H, 0.05
h.sup.-1; K.sub.H,NH, 0.05 mg (N)/L; K.sub.H,O, 0.2 mg (N)/L;
{circumflex over (.mu.)}.sub.A, 0.3 h.sup.-1; f.sub.H,DON, 0.04;
Y.sub.A, 3.4 mg (COD)/mg (N); b.sub.A, 0.15 h.sup.-1; K.sub.A,NH, 5
mg (N)/L; K.sub.A,O, 0.4 mg (N)/L; f.sub.A,DON, 0.04; i.sub.XP,
0.03 mg (N)/mg (COD); f.sub.NO, 0.8; f.sub.I, 0.2; K.sub.H,DON, 1.5
mg (N)/L.
[0050] Predicting the concentration of the mDON in wastewater: the
components of influent and values of model parameters determined in
2) were fed into the software for modeling mDON to predict the
concentration of the mDON in wastewater; where the single-step size
was 0.1, and the calculation capacity was 240 steps. The
model-predicted concentration of the mDON yielded in the oxidation
ditch was 2.32 mg/L.
Example 3
[0051] The example was the same as Example 2, except for the
influent coming from the municipal wastewater treatment plant A was
sampled at different times. The operating parameters of the
sequencing batch reactor: the influent temperature was 20.degree.
C., and hydraulic retention time was 8 h, activated sludge age was
5 d. The influent contains the following compositions: COD
96.2-120.6 mg/L, total nitrogen 23.7-29.1 mg/L, total phosphorus
2.0-3.5 mg/L, pH 7.4-8.0, and inert particles 3000-3200 mg/L. The
influent (of greater than 200 mL) in the biological treatment
process (i.e. oxidation ditch) and the activated sludge (of greater
than 50 mL) were sampled for analysis of the components of the
influent and parameter estimation. The influent sample was then
filtered using a cellulose acetate membrane filter having pore size
of 0.45 .mu.m. COD was measured by using potassium dichromate
method or rapid digestion method; the concentration of total
nitrogen was measured by using potassium persulfate oxidation-ion
chromatography, or potassium persulfate oxidation-ultraviolet
spectrophotometry; the concentration of ammonia nitrogen was
measured by using salicylic acid-hypochlorite spectrophotometry;
the nitrate nitrogen was measured by using the ion chromatography
or ultraviolet-visible spectrophotometry; the nitrite nitrogen was
measured by using ion chromatography or
N-(1-naphthyl)-ethylenediamine spectrophotometry; the concentration
of dissolved organic nitrogen was the difference between the sum of
total nitrogen and ammonia nitrogen and the sum of nitrate nitrogen
and nitrite nitrogen. According to the parameters determined in 1),
the initial values of the yield coefficient (Y.sub.H) of
heterotrophic bacteria, the attenuation coefficient of
heterotrophic bacteria, and the maximum specific growth rate (PH)
of heterotrophic bacteria were 0.26 mgCOD/mgN, 0.09 h.sup.-1, and
1.0 h.sup.-1, respectively.
[0052] Building the ASM-mDON model and finding the optimal
parameter values i.sub.XB by parameter estimation: 0.07 mg (N)/mg
(COD); k.sub.a, 0.04 L/(mg (N)d); {circumflex over (.mu.)}.sub.H,
1.0 h.sup.-1; Y.sub.H, 0.30 mg (COD)/mg (N); b.sub.H, 0.05
h.sup.-1; K.sub.H,NH, 0.05 mg (N)/L; K.sub.H,O, 0.2 mg (N)/L;
{circumflex over (.mu.)}A, 0.3 h.sup.-1, f.sub.H,DON, 0.04;
Y.sub.A, 3.4 mg (COD)/mg (N); b.sub.A, 0.15 h.sup.-1, K.sub.A,NH, 5
mg (N)/L; K.sub.A,O, 0.4 mg (N)/L; f.sub.A,DON, 0.04; i.sub.XP,
0.03 mg (N)/mg (COD); f.sub.NO, 0.8; f.sub.I, 0.2; K.sub.H,DON, 1.5
mg (N)/L.
[0053] Predicting the concentration of mDON in wastewater: the
components of influent and values of model parameters determined in
2) were fed into the software for modeling mDON to predict the
concentration of the mDON in wastewater; where the single-step size
was 0.1, and the calculation capacity was 240 steps. The
model-predicted concentration of the mDON yielded in the oxidation
ditch was 1.89 mg/L.
Example 4
[0054] The example was the same as Example 1, except for the
influent from the municipal wastewater treatment plant B. The
operating parameters of the sequencing batch reactor: the influent
temperature was 20.degree. C., and hydraulic retention time was 6
h. activated sludge age was 30 days. The influent contained the
following compositions: COD 130.9 mg/L, total nitrogen 25.1 mg/L,
total phosphorus 5.1 mg/L, pH 7.2, and inert particles 3000-3200
mg/L. The influent (of greater than 200 mL) in the biological
treatment process (i.e. oxidation ditch) and the activated sludge
(of greater than 50 mL) were sampled for analysis of the components
of the influent and parameter estimation. The influent sample was
then filtered using a cellulose acetate membrane filter having pore
size of 0.45 .mu.m. COD was measured by using potassium dichromate
method or rapid digestion method; the concentration of total
nitrogen was measured by using potassium persulfate oxidation-ion
chromatography, or potassium persulfate oxidation-ultraviolet
spectrophotometry; the concentration of ammonia nitrogen was
measured by using salicylic acid-hypochlorite spectrophotometry;
the nitrate nitrogen was measured by using the ion chromatography
or ultraviolet-visible spectrophotometry; the nitrite nitrogen was
measured by using ion chromatography or
N-(1-naphthyl)-ethylenediamine spectrophotometry; the concentration
of dissolved organic nitrogen was the difference between the sum of
total nitrogen and ammonia nitrogen and the sum of nitrate nitrogen
and nitrite nitrogen. According to the parameters determined in 1),
the initial values of the yield coefficient (Y.sub.H) of
heterotrophic bacteria, the attenuation coefficient of
heterotrophic bacteria, and the maximum specific growth rate
({circumflex over (.mu.)}.sub.H) of heterotrophic bacteria were 0.2
mgCOD/mgN, 0.05 h.sup.-1, and 0.3 h.sup.-1, respectively.
[0055] Building the ASM-mDON model and finding the optimal
parameter values i.sub.XB by parameter estimation: 0.07 mg (N)/mg
(COD); k.sub.a, 0.04 L/(mg (N)d); {circumflex over (.mu.)}.sub.H,
0.33 h.sup.-1; Y.sub.H, 0.32 mg (COD)/mg (N); b.sub.H, 0.05
h.sup.-1; K.sub.H,NH, 0.05 mg (N)/L; K.sub.H,O, 0.2 mg (N)/L;
{circumflex over (.mu.)}.sub.A, 0.3 h.sup.-1; f.sub.H,DON, 0.04;
Y.sub.A, 3.0 mg (COD)/mg (N); b.sub.A, 0.15 h.sup.-1; K.sub.A,NH, 5
mg (N)/L; K.sub.A,O, 0.4 mg (N)/L; f.sub.A,DON, 0.04; i.sub.XP,
0.03 mg (N)/mg (COD); f.sub.NO, 0.8; f.sub.I, 0.2; K.sub.H,DON, 1.5
mg (N)/L.
[0056] Predicting the concentration of mDON in wastewater: the
components of influent and values of model parameters determined in
2) were fed into the software for modeling mDON to predict the
concentration of the mDON in wastewater; where the single-step size
was 0.1, and the calculation capacity was 60 steps. The
model-predicted concentration of the mDON yielded in the oxidation
ditch was 4.31 mg/L.
Verification Example
[0057] The influent entering the sequencing batch reactor in
Example 1 was sampled to measure the concentration of the mDON that
was then verified with the model-predicted concentration. The
operating cycle for the sequencing batch reactor was 5 h, under
which the influent was sampled per 0.5 h interval. The influent
samples were filtered and used to undergo measurement with
reference to the methods described in Example 1. Referring to FIG.
3, the measured concentration of the mDON in the entire operating
cycle was basically fitted to the model-predicted concentration,
lying in the calculated error range.
[0058] In summary, the measured concentration of the mDON is close
to the model-predicted concentration of the mDON yielded in the
activated sludge process in accordance with the Verification
Example of the disclosure. The disclosure offers many advantages in
simplicity, accuracy, and fast prediction over current methods,
thereby being widely applied in prediction of the mDON yielded in
activated sludge process.
[0059] It will be obvious to those skilled in the art that changes
and modifications may be made, and therefore, the aim in the
appended claims is to cover all such changes and modifications.
* * * * *